Cut-out.



m 70,201. Patented Dec. 30, I902.

J. w. HOWELL. Y

CUT-OUT.

(Application filed Feb. 2. 1901.)

(lo Model.)

, Inventor". John W. Howell,

UNITED STATES l PATENT OFFICE.

JOHN IV. HOWELL, OF NEW'ARK, NEW JERSEY, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

CUT-OUT.

SPECIFICATION formingpart of Letters Patent No. 717,201, dated December1902.

Application filed February 2, 1901. Serial No. 45,732. (No model.)

To (tZZ whom it may concern:

Be it known that I, JOHN W. HOWELL, a citizen of the United States,residing at Newark, county of Essex, State of New Jersey, have inventedcertain new and useful Improvements in Out-Outs, (Case No. 1972,) of

which the following is a specification.

This invention relates to circuit-controllers of that type commonlycalled cut-outs, by which a circuit or branch normally open is closed bythe rupture of a dielectric between two contact points or surfaces whenthe potential at the opposing surfaces reaches a determinate value.These devices are frequently made by interposing thin films ofinsulating substance or fabric between two contact points or surfaces,which is broken down when the potential reaches the jumping-point. Thedevices are commonly placed in shunt to the translating device, such asan incandescent or an arc lamp, used on a series circuit, which shuntremainsopen by reason of the insulating properties of the dielectricbetween the contact-surfaces so long as the lamp is in working order;but if the mechanism of the arc-lamp becomes deranged, preventing theare being struck, or the filament breaks or burns out the increase ofpotential ruptures the film and closes the shuntcircuit, therebypreserving the series circuit in working order. Adifficulty arises inthe use of these paper cut-outs from the unevenness of thickness of thepaper fabric. The parts have been commonly arranged so that one of thecontact-plates is provided with a point or struck-up protuberancebearingon the paper, and by reason of thin spots in the paper the pointat which it will puncture is uncertain, so that the cut-out may breakdown at a lower potential than that intended or may not break down whenit should. I find by experience that'by forming the cut-out of two metalplates having perfectlyflat surfaces between which is placed a film ofpaper much more uniform results are secured. I preferably soak the paperin shellac-varnish and permit it to dry and then press it between twoperfectly flat metal plates, heating it and permitting it to cool whileunder pressure, thereby forming a single unit of the completed device,

the parts of which are not separated, and providing for the exclusion ofmoisture from the opposing surfaces, thereby rendering the cut-outuniform in action and responsive to a predetermined potential.

The novel features of the invention will be more specifically pointedout hereinafter and will be definitely indicated in the claims appendedto this specification.

In the accompanying drawings, Figure 1 is a side elevation, partly insection, of a series incandescent lamp to which my improved cut-out hasbeen applied. Fig 2 is a top plan view of such a lamp. Figs. 3, 4E, and5 are perspective views showing the construction of my cut-out. Fig. 6is a sectional elevation of a modified form of socket for anincandescent lamp-to which the cut-out may be applied.

Referring first to the detail views, Figs. 3, 4:, and 5, the completedevice is shown in Figs. 3 and 5, the former a rectangular type and thelatter a circular type. 1 1 represent two plates of metal polished onone face, and 2 a sheet of tissue-paper, for which I prefer to useJapanese paper about three-fourths millimeter in thickness, soaked in analcoholic solution of shellac and dried. This is placed between thesmooth faces of the plates, heated, and put in a clamp and permitted tocool, and by this means the two plates are separated a uniform distancein all specimens of the device, the fiat faces of the plates preventingthem from approaching if a thin spot occurs in the paper, as is the casewith types of these devices where two rounded contacts are employed. Thesize of the plates may vary; but I have found that pieces ofmetalone-fourth by one-half inch are a convenient size to employ inpractice and givesatisfactory results. The shellac causes perfectadhesion of the pieces and permits the device to be handled as a unitwithout loss of any of the parts and preserves a uniform rupture-pointby preventing entrance of moisture to the contact-faces. The device maybe employed with any'type of translating device where it is desired toclose a circuit when the dielectric breaks down.

In Figs. 1, 2, and 6 I have shown the device as applied to a seriesincandescent lamp, the cut-out being placed in shunt to thelamp-terminals, as shown at 4, 5 being a metal tongue screwed fast toone terminal and lying over the brass ring 6, connected with the otherterminal in such relation that when the cutout is slipped under thetongue a shunt to the lamp-filament is completed, open only at thedielectric film between the plates 1 1 of the cut-out.

The lamp shown is of a well-known form of construction and need not bedescribed in detail.

In Fig. 6 the cut-out is shown at 4 as interposed between two fiexiblestrips 7 7 connected to the terminals of the lamp-socket and adapted tobe inserted between two spring tongues 8 8, mounted on a fixedswitchboard or base at which the circuit connections are made. With thisconstruction the lamp and its socket may be withdrawn from theswitchboard and the film cut-out inserted between the springs '7 7 andthe whole then inserted in the switchboard. So long as the lamp isacting properly the film remains intact; but if the lamp-filament shouldbecome broken or ruptured the film is broken down and cross connectionmade between springs 7 7, thereby completing the line-circuitindependent of the lamp.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. A cut-out for a translating device, comprising two fiat metallicsurfaces having interposed between them a thin film of a dielectricmaterial, the whole being bound together so as to be handled as a unit.

2. A cut-out for a translating device, composed of plates of metalseparated by an insulating-film and secured together so as to be handledas a unit.

3. A cu t-out for a translating device adapted for insertion betweenspring-jaws, comprising two rigid pieces of metal having an interveningsolid insulatingfilm held between similarly-shaped opposing surfacescoincident with the opposite surfaces of the film to provide aconsiderable area of contact.

4. A film cut-out for a translating device, comprising two rigid platesmade of metal having true parallel surfaces separated by a film ofshellacked insulating fabric and pressed together with uniform pressureover a wide contact-surface.

5. A film cut-outfor an electric translating device, comprising twopieces of metal having true opposing surfaces separated by a shellackedfilm of insulating material and held in adhesive engagement by saidshellacked film.

6. A cut-out for an electric translating device, comprising two fiatpieces of metal having smooth opposing surfaces, and an intervening filmof shellacked paper adhering to the surfaces.

In witness whereof I have hereunto set my hand this 31st day of January,1901.

JOHN W. HOWELL.

Witnesses:

S. N. WHITEHEAD, J 0s. D. FREDERICKS.

